Meeting paper
SMFM paper
PreImplantation Factor (PIF) orchestrates systemic antiinflammatory response by immune cells: effect on peripheral blood mononuclear cells

Presented orally at the 32nd annual meeting of the Society for Maternal-Fetal Medicine, Dallas, TX, Feb. 6-11, 2012.
https://doi.org/10.1016/j.ajog.2012.07.017Get rights and content

Objective

Embryo-derived PreImplantation Factor (PIF) is essential for pregnancy immune modulation and synthetic PIF (sPIF), reverses neuroinflammation, and prevents diabetes mellitus through its immune modulatory properties. Herein, we explore sPIF's systemic effects on peripheral blood mononuclear cells (PBMCs).

Study Design

sPIF's effects on PBMCs and subset populations from nonpregnant patients (n = 7) and male patients were evaluated by the assessment of binding characteristics, mixed lymphocyte reaction, proliferation, cytokine secretion, and associated gene expression. Data analysis was by analysis of variance (P < .05).

Results

Fluorescein isothiocyanate–sPIF bound all myelomonocytic cells; binding was 30-fold up-regulated in mitogen-activated T and B cells (P < .05). sPIF decreased mixed lymphocyte reaction by 70% and blocked anti-CD3 antibody stimulated-PBMC proliferation by approximately 80% (P < .05). In naïve PBMCs, sPIF reduced interleukin (IL)-10 and -2; in activated PBMCs, sPIF increased IL-4, -5, -10, and -2, tumor necrosis factor–α, interferon-γ, and granulocyte-macrophage colony-stimulating factor (P < .05).

Conclusion

Physiologic concentrations of PIF exert potent systemic antiinflammatory effects on nonpregnant activated immune cells.

Section snippets

PIF peptide isolation and synthesis

Partial characterization and PIF assay information was published previously.21, 22 Briefly, 1 L of mouse embryo that had been conditioned in culture media or control media was filtered through a 3 kd YM membrane (Millipore Corporation, Bedford, MA) and was passed through an affinity column (Anti-CD2 T11-1-antibody; BD Pharmingen, San Diego, CA) with Affi-Gel Hz Immunoaffinity (Bio-Rad Laboratories, Hercules, CA).32 Eluted fractions with PIF activity passed through C18 (Clipeus) high-performance

Predicted 3-dimensional structure; homology to malaria protein

Isolation of PIF from conditioned mouse embryo culture media vs media alone, control was carried out (Figure 1). PIF is a 15 aa peptide; where the first 9 aa are common for all 4 peptides (Figure 2, A and B). Figure 1, C and D, shows a predicted 3-dimension PIF (15 aa) image. We found that the 15 aa peptide (PIF) is by far the most abundant peptide in the embryo culture media, based on mass spectrometry. Therefore, the sPIF 15 aa (sPIF) was used for all experiments that assessed its interaction

Comment

Pregnancy-associated compounds inherently provide a fertile field of investigation for immune modulation without suppression, tolerance development, inflammation, and engraftment control. Herein, we document that PIF, an embryo-secreted peptide, modulates systemic human PBMC function. We demonstrate that sPIF offers a dual complementary mode of action that is highly dependent on the immune scenario that is involved: basal or challenged. In naïve PBMCs, sPIF binds macrophages and reduces TH1/TH2

Acknowledgments

We thank P.C. Leavis (Boston Biomedical Research Institute, Boston, MA), R.R. Gonzalez, (formerly of the Boston Biomedical Research Institute), and M. Barzani (Bio-Synthesis, Inc, Lewisville, TX) for their assistance in isolating and synthesizing PreImplantation Factor; C. Wiggins (Bioinformatics Solutions Inc, Waterloo, Ontario, Canada) for assistance in the 3-dimensional structure of PreImplantation Factor; A. Bulman (Ciphergen Systems, Freemont, CA) for analyzing the embryo culture media; R.

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      In contrast, “scrambled PIF” (same amino acids as PIF, but in random order, used as control) had no effect, indicating that the PIF effect is selective. PIF regulates PBMCs cytokine secretion and related gene expression (Barnea, 2007b; Barnea, Kirk, et al., 2012; Barnea, Rambaldi, Paidas, & Mecacci, 2013). PIF reduced cytokines in unstimulated PBMCs.

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    Supported in part by a grant from the Consortium for Industrial Collaboration in Contraceptive Research of CONRAD (Arlington, VA), a Division of the Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Norfolk, VA (E.R.B., principal investigator).

    PreImplantation Factor (PIF) is a proprietary compound owned by BioIncept, LLC. E.R.B. is its (uncompensated) Chief Scientist; J. H. Barnea LLD, (uncompensated) President and CEO, is majority shareholder. Yale University received an unrestricted grant (M.J.P.). S.R. and R.R. received funding from BioIncept, LLC. D.K. and B.R. declare no conflict of interest.

    Cite this article as: Barnea ER, Kirk D, Ramu S, et al. PreImplantation Factor (PIF) orchestrates systemic antiinflammatory response by immune cells: effect on peripheral blood mononuclear cells. Am J Obstet Gynecol 2012;207:313.e1-11.

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